1. Technical Field
The present invention relates, generally, to placement of bonding pads and supporting circuitry on integrated circuit (IC) devices and, more particularly, to techniques for locating bonding pads and the associated supporting circuitry on different sides of an IC fabrication die.
2. Statement of the Problem
It is desirable in the fabrication of semiconductor devices to produce as many devices from a single wafer as possible. Increasing the number of die (from which the devices are fabricated) per wafer can be accomplished by increasing the size of the wafer and/or decreasing the size of the die. In either case, the probe yield (the percentage of good devices present on the wafer) is improved. However, known methods for minimizing the device die size employ the relatively time-consuming and costly task of customizing the IC layout and/or core circuitry.
A typical semiconductor device such as an integrated circuit (IC) has four sides, from each of which extend a number (typically 32) of `external connecting pads`. Each external connecting pad is typically comprised of a bonding pad and an associated support circuit pad containing active support circuitry. Bonding pads are employed to establish contact points to which electrical connections are established (via a wire bond or the like) between the IC and an external circuit. The support circuitry associated with the various active bonding pads typically functions to protect the IC circuitry from deleterious electrical phenomenon such as electrostatic discharge (ESD) and latchup. Additional details regarding wire bonding and related techniques may be found in a number of standard references, for example, SERAPHIM ET AL., PRINCIPLES OF ELECTRONIC PACKAGING (1989).
Existing methods which attempt to reduce the device die size by customizing the IC layout or core circuitry may provide only limited decrease in die size because of design rules which require minimum sizes for bonding and support circuit pads in order to provide ESD/latchup immunity and sufficient bonding area.
A method is therefore needed to overcome these and other limitations of the prior art.